Unknown primary cancer

Introducing unknown primary cancer

What are lymph nodes?

Lymph nodes are bean shaped glands in the neck that are part of the immune system’s defence against infection. There are hundreds of lymph nodes in the head and neck area and the majority of these run down the sides of the neck and under the jaw. Lymph nodes are normally difficult to feel because they are soft and small (less than 1 cm). The lymph nodes may become swollen during infection or due to cancer.